KR101414698B1 - Method and device for determining an operating characteristic of an injection system - Google Patents

Abstract

The present invention relates to a method and apparatus for determining operating characteristics of an injection system. The object of the present invention is to determine the operating characteristics of the internal combustion engine 1 occupied by the turbocharger 40. [ To this end, the method comprises A) injecting fuel into the cylinders 51, 52, 53, 54 of the internal combustion engine 1 using the injection system 30; B) determining an operating parameter of the turbocharger (40); C) determining operating characteristics of the injection system (30) using previously determined operating parameters of the turbocharger (40); / RTI >

Description

Technical Field [0001] The present invention relates to a method and apparatus for determining an operating characteristic of an injection system,

The present invention relates to a method for determining an operating characteristic of an injection system of an internal combustion engine as claimed in claim 1 and a controller for performing the method claimed in claim 10.

In modern internal combustion engines, it is important to obtain a precisely specified fuel injection quantity in order to obtain the best exhaust gas emission values. Moreover, efforts are being made to obtain the most stable and quietest possible consistent engine operation, ensuring that as much fuel as possible is injected into all cylinders in the case of multi-cylinder engines. The injection pattern based on the amount of fuel injected here must be homogeneous ie the same number of tests per cylinder, main injection and post injection. For example, if the injection pattern for each cylinder consists of one main injection per combustion cycle, the injection times relative to the predetermined operating point of the internal combustion engine (injection time is generally the crankshaft angle of the piston Position), as well as to ensure that the injection quantities per injection remain the same for all cylinders.

It is difficult to obtain a predetermined injection amount due to manufacturing tolerances of the controllers and individual components of the injection system. In particular, the injectors may have manufacturing tolerances that cause different injection quantities despite the same given operating parameters and ambient conditions. Furthermore, the components (injectors to be mentioned again in this respect once again) undergo a change in the operating characteristics according to their service life and, if a countermeasure is not taken, the change in the quantity of injection thus obtained thereby. The change in operating parameters over the lifetime of the component is also referred to as drift.

To solve the manufacturing tolerances and drift problems, it is desirable to adjust the injection parameters of the injectors individually for each of the cylinders, for example to obtain the same injection patterns for all the cylinders. To do this, information about the current operating characteristics of each injector should be known. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to determine operating characteristics of an injection apparatus of an internal combustion engine.

The problem to be solved by the present invention is solved by the features mentioned in claim 1 and the features mentioned in independent claim 10. Beneficial embodiments of the invention are disclosed in the dependent claims.

In an internal combustion engine including an injection system and a turbocharger, the injection system performs fuel test injection into the cylinder of the internal combustion engine. Determine the operating parameters of the turbocharger. Determines operating characteristics of the injection system based on the determined operating parameters of the turbocharger.

The test injection causes a change in the amount of energy of the exhaust gas driving the turbocharger (in particular the outflow rate and temperature from the cylinder). The change in the amount of energy is reflected in the changed operating parameters of the turbocharger. Thus, as a result of the test injection, operating parameters such as rotational parameters or temperature of the turbocharger, for example, generally vary. The term "rotation parameters" includes in particular the rotational speed, angular momentum and torque of the turbocharger. Changes in operating parameters can be used to draw conclusions about the injection system. By performing the test spraying, it is possible to detect, measure and, if necessary, compensate for manufacturing tolerances or drift, especially of the sprayer.

It is concluded that the injector has allowed more than the average injection amount into the cylinder if the test injection has produced, for example, greater than the average rotational speed of the turbocharger for a predetermined activation period of the injector. This pure qualitative deduction already constitutes useful operating characteristics of the injector. This can be used, for example, by a control loop in which the operating parameters of the turbocharger are fed back to the injector by negative feedback to more accurately control the injector and to obtain a more precise injection quantity.

However, the operating characteristics of the injection system can also be variables that can be derived from quantitative variables, for example injection quantity or injection quantity. If so, it is determined based on the operating parameters of the turbocharger. However, quantitative operating characteristics of this type can be determined in a variety of ways. One possibility for this is the thermodynamic simulation of the internal combustion engine in the electronic control unit. In this case, for example, the injection amount of the test injection is determined based on the rotational speed change of the turbocharger. However, thermodynamic simulations are not the only possible way to determine the operating characteristics of the injection system. The influence of the test injection amount injected in advance in the test or simulation on the operation parameters of the turbocharger may be determined and stored in the engine characteristic map assigned to the electronic control unit. The quantitative value of the operating parameter (for example a change in the rotational speed) which may be due to the test injection may then be transmitted to the electronic control unit during normal operation of the internal combustion engine. Then, for example, only the electronic control unit needs to read the value "amount of injection" corresponding to the determined operating parameter from the engine characteristic map. The advantage of the engine characteristic map over the thermodynamic simulation is that it can essentially reduce the computational overhead very much.

The term "operating parameter" does not include only qualitative and quantitative parameters cited by way of example above. For example, instead of determining the amount of fuel injected based on the measured turbo supercharger rotation speed in the engine characteristic map, for example, a mapping that directly maps the operating parameters of the turbocharger onto the control parameters of the injection system, Lt; / RTI > The engine characteristic map may include, for example, mapping of the turbo supercharger rotational speed change onto the correction period or active period of the active period of the injector for performing the test injection. Thus, for example, a shorter activation period means an injector having a high fuel throughput due to, for example, manufacturing tolerances and / or drift. Thus, the activation period of the injector, for example, represents the operating characteristics of the injection system, for example.

The term "operating parameters of the turbocharger" also includes variations to the operating parameters and deviations from the target value, such as deviation of the rotational speed variation from the target value, which would be expected as a result of the test injection.

By performing a number of test injections, it is possible to more accurately determine the variables that can be derived from the injection quantity or injection quantity. In this case, it is possible to measure the variable related to the rotation speed or the rotation speed of the turbocharger within a short time after each test injection. Then, using statistical methods such as, for example, average, the variables that can be derived from the injection quantity or the injection quantity can be more accurately determined.

However, it is also possible to perform multiple test injections and only determine the overall effect of the test injections on the rotational parameters of the turbocharger. This makes it possible to more accurately determine manufacturing tolerances and drifts, especially in the dynamics of the opening and closing operations of the injectors. Preferably, the test injections are carried out consecutively.

In another preferred embodiment, test or test jets are made in a torque-neutral manner with respect to the crankshaft driven by the internal combustion engine. This means that the injection is performed so as not to work or at least not work at least in the cylinder piston. Thereby providing an outlet velocity and heat of the exhaust gas. As a result, the operating characteristics of the injection system can be determined more accurately and easily. In particular, torque neutral injection can be performed by appropriately selecting the injection time. For many internal combustion engines, this injection time is given, for example, close to the bottom dead center, just before the exhaust valve closes.

The present invention can be embodied such that the present method is continuously performed during operation of the internal combustion engine. However, since the drift of modern injection systems proceeds relatively slowly, it is particularly desirable to perform the method at time intervals that correct the injection system.

Also in another preferred embodiment, using the method according to the invention, the deviation of the determined operating parameters from the target value can be used to obtain the same or different target values, in particular the target injection quantity, more accurately in the subsequent injection.

In another preferred embodiment, the method according to the invention is carried out for a plurality of cylinders of the internal combustion engine, preferably for all cylinders of the internal combustion engine. It is then possible to properly activate each of the injectors to obtain uniform injection patterns for all the cylinders, thereby creating a particularly quiet operation of the internal combustion engine.

The present invention will now be described in more detail with reference to the accompanying drawings, in which:

Figure 1 shows a simplified engine;

Figure 2 shows the spray patterns for the four injectors with manufacturing tolerances;

Figure 3 shows the spray patterns for four injectors when one injector is test injected;

Figure 4 shows the injection patterns for the four injectors when the activation of one injector is corrected and the other injector performs the test injection;

Figure 5 shows the injection pattern with the activations corrected.

1 shows an engine in an embodiment of the present invention. The engine 1 includes an engine control unit (ECU) 10, an injection system 30, a turbocharger 40, and an engine block 50.

The injection system 30 consists of a common rail system. The injection system 30 includes a pressure accumulator 36 and four injectors 31, 32, 33, 34 connected to the pressure accumulator 36.

The engine block 50 includes four cylinders 51, 52, 53, 54. One of the injectors 31, 32, 33, 34 is assigned to each of the cylinders 51, 52, 53,

The turbocharger 40 can be driven by the combustion gas discharged from the cylinders 51, 52, 53 and 54 and compressed air is supplied through the turbocharger 40 to the cylinders 51, 52, 53, The turbocharger 40, which can be introduced into the combustion chamber of the engine block 50, is connected to the engine block 50. The turbocharger 40 includes a turbocharger measuring device 42 that measures the rotational speed of a turbine (not shown here) of the turbocharger 40.

The ECU 10 includes an electronic circuit 11, an injector-side interface 12, and a turbocharger-side interface 13. The ECU 10 is connected to the turbocharger measuring means 42 via the turbocharger side interface 13. [ The ECU 10 is connected to each of the injectors 31, 32, 33, and 34 via the injector side interface 12.

The electronic circuit 11 includes an engine characteristic map 14, a memory area 15 for storing parameters of the test injections, memory areas 21 and 22 for determining and storing operating characteristics of the injection system 30 , 23 and 24, a logic circuit 16 and an AD converter 17 (analog / digital converter).

The memory area 21 allows read and write access and is provided for the purpose of determining and storing the operating characteristics of the injector 31. The memory area 21 has a memory area 21a for storing the rotational speed when the test injection is not performed and a memory area 21b for storing the rotational speed in the case of performing the test injection through the injector 31 And a memory area 21c for storing a change in rotation speed. The memory areas 22,23 and 24 are similarly provided for the determination and storage of the respective operating characteristics of the other injectors 32,33 and 34 and similarly the memory areas 22a, 22b, 22c, 23a, 23b, 23c, 24a, 24b, 24c.

The engine characteristic map 14 can be made as a simple mapping that maps the variation of the rotational speed onto the correction of the activation duration. In one preferred embodiment, however, the engine characteristic map 14 may be implemented as a multidimensional mapping that maps the operating points of the internal combustion engine and the rotational speed of the turbocharger 40 onto the correction of the active period of the injectors . The engine characteristic map 14 is measured and initialized in the test or simulation before normal operation of the internal combustion engine. In such an embodiment, normally the engine characteristic map 14 would not need to be changed for the entire life of the internal combustion engine.

The values of the activation period and the start time during the test injection are stored in the memory area 15 at the angle degrees. The values are preferably selected so as to result in torque-neutral test injection. The memory area 15 may be implemented as pure read-only access memory.

The principles of operation of the exemplary embodiment of FIG. 1 will now be described in more detail with reference to the injection schemes shown in FIGS. 2-5. 2 to 5 show timing sequences of the injectors performed by the four injectors 31, 32, 33, and 34. As shown in FIG. In each of the figures, the horizontal axis represents the time t, and the m axis represents the injection amount of the injection. Herein, the injection 31r represents a normal injection of the injector 31. [ Similarly, each of the injections 32r, 33r, 34r represents normal injections of the injectors 32, 33, 34. m0 represents a predetermined target injection amount for a predetermined operating point of the internal combustion engine.

Figure 2 shows a sequence of injections into four cylinders 51, 52, 53, 54 at constant operating points of the internal combustion engine, preferably during idle idling. Referring to FIG. 2, it can be seen that the injectors 31, 32, 34 eject the injected amount different from the target value due to manufacturing tolerances and / or drift. Due to the manufacturing tolerances and drift, different injectors can provide different injections, despite the prerequisite for the same activation of the injectors. 2, the injection amounts of the injectors 31 and 34 are too large in comparison with the target injection amount m0, and the injection amounts of the injectors 32 are too small in comparison with the target injection amount m0. Only the injector 33 ejects the correct injection amount. The turbocharger measuring device 42 measures the first rotational speed of the turbocharger 40 for the first time and the first rotational speed of the turbocharger 40 is equal to the first rotational speed of the turbocharger 40, (21a). Then, the internal combustion engine 1 transitions to the operation mode corresponding to the injection pattern shown in Fig.

Fig. 3 shows the sequences of injections into four cylinders 51, 52, 53, 54 at the same operating point of the internal combustion engine as in Fig. The four injectors 31, 32, 33, and 34 are controlled so that the normal injections 31r, 32r, 33r, and 34r are performed in exactly the same manner as in Fig. Incidentally, the injector 31 performs the test injection 31T. For test injection, the ECU 10 controls the injector 31 using certain control parameters stored in the memory area 15. Test injection is performed in a torque-neutral manner. The rotational speed change of the turbocharger 40 is indicated by the test injection. As soon as the turbocharger 40 reaches a stationary operating state, the turbocharger measuring device 42 measures the second rotational speed and the second rotational speed of the turbocharger 40 is stored in the storage area 21b .

Next, the logic circuit 16 forms the difference between the first and second rotational speeds to calculate the change in the rotational speed, and the change in the rotational speed is stored in the memory area 21c. The rotational speed will change more than the average amount due to the test injection 31T performed by the injector 31 in the example shown in Figure 3 because the injector 31 is larger than the average fuel amount in the case of the fixed activation period It is because it injects the quantity. As a result, the change in the calculated rotation speed for the injector 31 will be larger than the change in the predetermined target rotation speed.

The correction value of the activation period is read out from the engine characteristic map 14 with respect to the change of the calculated rotation speed. In the cited example of the injector 31, the activation period should be shorter. The logic circuit 16 adjusts the activation period of the injector 31 so that the target injection amount m0 is obtained with respect to the injector 31 with the help of the activation interval correction value stored in the memory area 21c.

The correction of the active period can be stored, for example, as a coefficient that should be multiplied by the original active period. In a simpler modification, the engine characteristic map 14 may be made as a pure mapping that maps the variation of the rotational speed to the correction phase of the active period. However, this type of engine characteristic map 14 results in an accurate correction only for those operating points for which the engine characteristic map was previously measured. At other operating points it merely represents an approximation of the optimal correction of the active period. Thus, in a preferred embodiment, the engine characteristic map 14 is stored as a multi-dimensional engine characteristic map that maps changes in the load of the internal combustion engine, the rotational speed of the internal combustion engine, and the rotational speed of the turbocharger to the correction phase of the active period. Mathematically speaking, this is mapping space R ³ to R. In order to be able to read the correction value for the injection period in this modification, the ECU 10 additionally has knowledge about the operating point of the internal combustion engine. Such information is always practically always present in the ECU 10.

4 shows the relationship between the four cylinders 51, 52, 53, 54 of the internal combustion engine 51 whose activation of the injector 31 is adjusted in accordance with the correction of the activation period determined in the engine characteristic map 14 so as to obtain the target injection amount m0. ). ≪ / RTI > Similar to the procedure for the injector 32 described above, the activation of the injector 32 is now corrected. Here, the rotational speed of the turbocharger is measured for the first time without test injection, and then the rotational speed of the turbocharger is measured while performing the test injection (32T) by the injector 32. The correction value of the injection period related to the speed of the rotation speed is read out again from the engine characteristic map 14. [

Figure 5 shows the injection patterns of the injectors 31, 32, 33, 34 after each of the injectors 31, 32, 33, 34 is set in succession. In FIG. 5, it can now be seen that all the injectors 31, 32, 33, 34 provide the same injection quantities. It should be noted here that the present invention is also of course not limited to engines having four cylinders.

It should also be noted that the test injection need not be torque-neutral, since the result of the reduction in heat produced by the work done in the piston can also be taken into account in the engine characteristic map by simulation or testing.

It should be noted that the test injection need not be a separate injection. This also makes it possible, for example, to initially measure the first rotational speed as described above with reference to FIG. Instead of what is shown in Fig. 3, however, instead of performing a separate injection 31T with the injector 31 to determine the second rotational speed, instead the injections 31r are extended by a predetermined time interval . The change in the rotational speed of the turbocharger, which can be measured thereby, can also be used for the purpose of adjusting the activation of the injector 31 by means of an appropriately measured engine characteristic map.

For example, the control parameters of the injection system such as the correction of the injection interval need not be stored as coefficients. At the same time, the correction can be performed using a summand or other appropriate function.

The injection quantity can not be corrected only by the injection interval; Rather, through the control signal level for the injector, for example via the voltage curve of the control signal, the injection quantity can also be corrected.

It should also be noted that the present invention is not limited to determining one correction parameter for each injector, for example a change in the rotational speed stored in the memory area 21c. At the same time, it is also readily possible to determine and store a plurality of correction parameters for the injector, for example as a multidimensional engine characteristic map, by means of the method according to the invention in the multidimensional engine characteristic map for different operating points of the internal combustion engine And the change in rotational speed appearing in the turbocharger as a result of the test injection for different rail pressures is measured.

Claims (18)

A) injecting fuel into the cylinders (51, 52, 53, 54) of the internal combustion engine (1) using the injection system (30); B) determining an operating parameter of the turbocharger (40); C) determining operating characteristics of the injection system (30) based on the determined operating parameters of the turbocharger (40); Comprising: A method for determining an operating characteristic of an injection system (30) of an internal combustion engine (1) including a turbocharger (40). The method according to claim 1, The operating parameters of the turbocharger (40) Rotation parameter, A method for determining an operating characteristic of an injection system (30) of an internal combustion engine (1) including a turbocharger (40). 3. The method according to claim 1 or 2, The operating characteristics of the injection system (30) Is a variable that can be derived from the injection amount or the injection amount. A method for determining an operating characteristic of an injection system (30) of an internal combustion engine (1) including a turbocharger (40). 3. The method according to claim 1 or 2, The steps of A) to C) Characterized in that it is carried out for a plurality of test jets. A method for determining an operating characteristic of an injection system (30) of an internal combustion engine (1) including a turbocharger (40). 3. The method according to claim 1 or 2, The test spray or test spray, In a torque-neutral manner. ≪ RTI ID = 0.0 > A method for determining an operating characteristic of an injection system (30) of an internal combustion engine (1) including a turbocharger (40). 3. The method according to claim 1 or 2, The correction of the injection system (30) And the operation parameter is determined based on the determined operation parameter. A method for determining an operating characteristic of an injection system (30) of an internal combustion engine (1) including a turbocharger (40). 3. The method according to claim 1 or 2, Using the deviation of the determined operating parameter from the target value to obtain the same or a different target value more accurately in the subsequent injection. A method for determining an operating characteristic of an injection system (30) of an internal combustion engine (1) including a turbocharger (40). 3. The method according to claim 1 or 2, Characterized in that the method is executed for a plurality of cylinders (51, 52, 53, 54) of the internal combustion engine (1) A method for determining an operating characteristic of an injection system (30) of an internal combustion engine (1) including a turbocharger (40). 3. The method according to claim 1 or 2, Characterized in that the method is used to obtain spray patterns which are as homogeneous as possible into the different cylinders (51, 52, 53, 54) A method for determining an operating characteristic of an injection system (30) of an internal combustion engine (1) including a turbocharger (40). A) an injector side interface (12) for controlling the injection system (30); B) a turbocharger side interface (13) for receiving operational parameters of the turbocharger (40); And C) an electronic circuit (11) configured to determine operating characteristics of the injection system (30) based on the operating parameters received at the turbocharger side interface (13) An apparatus for determining operating characteristics of an injection system. 11. The method of claim 10, The operating parameters of the turbocharger (40) Rotation parameter, An apparatus for determining operating characteristics of an injection system. The method according to claim 10 or 11, The operating characteristics of the injection system (30) Is a variable that can be derived from the injection amount or the injection amount. An apparatus for determining operating characteristics of an injection system. The method according to claim 10 or 11, The injector side interface 12 triggers test injection into the cylinders 51, 52, 53, 54 of the internal combustion engine 1, Characterized in that the test injection is performed in a torque-neutral manner. An apparatus for determining operating characteristics of an injection system. The method according to claim 10 or 11, The electronic circuit (11) So that correction of the injection system (30) can be performed based on the determined operating parameters. An apparatus for determining operating characteristics of an injection system. The method according to claim 10 or 11, And using the deviation of the determined operating parameter from the target value to obtain the same or a different target value more accurately in the subsequent injection. An apparatus for determining operating characteristics of an injection system. 14. The method of claim 13, Characterized in that the electronic control unit (10) performs test injections into the plurality of cylinders (51, 52, 53, 54) of the internal combustion engine (1) An apparatus for determining operating characteristics of an injection system. 14. The method of claim 13, The electronic control unit 10 controls the injection system 10 so as to obtain as homogeneous injection patterns as possible with respect to the different cylinders 51, 52, 53, 54 of the internal combustion engine 1 in consideration of the determined operating parameters. Characterized in that the electronic circuit (11) is embodied so as to control the electronic circuit (30) An apparatus for determining operating characteristics of an injection system. An electronic control unit (10) that functions as an operating characteristic determining device of the injection system according to claim 10 or claim 11, and an engine control unit Lt; / RTI > Internal combustion engine (1).

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